1. Field of the Invention
This invention lies in the field of the grinding and polishing of lens surfaces, such as for spectacles, in which the lens is held attached to a lens block, and is pressed against a lap of a selected curvature, etc.
Still more particularly, it concerns the apparatus for grinding a cylindrical lens, in which the lens block holding the lens is adapted to have rotation about its longitudinal and/or transverse axes, but no rotation about a vertical axis.
2. Description of the Prior Art
In the prior art there are a number of patents pertaining to the general art of grinding lenses, most of which have spherical surfaces, which require a type of movement of the lens block different from that provided in this apparatus.
In this apparatus the motion of the block is complex, having three degrees of eccentricity of motion, one of which is adjustable. Different relative phase angles, and different angular speeds are provided for the three components of motion, which are not shown in the prior art, and the output motion represented by a motion of an upright drive post, pivoted at its bottom end, is in a side-to-side and fore-and-aft motion but without any rotation about the longitudinal axis of the post. Thus the lens block moves parallel to itself without rotation about a vertical axis, while it is given random angular motions about its longitudinal and transverse horizontal axes.
The prior art fails to show this type of a drive system.